(a) Field of the Invention
The present invention relates to a cutting and sorting automation system, and more particularly to a system used in a TFT-LCD manufacturing process for simultaneously cutting and sorting substrates having defective cells. The present invention also relates to a method for controlling such a system.
(b) Description of the Related Art
The TFT-LCD (thin film transistor liquid crystal display) applies an electric field to a liquid crystal layer injected between two substrates. The liquid crystal has an anisotropic dielectricity. The two substrates, typically a TFT substrate and a CF (color filter) substrate, are arranged substantially in parallel having a predetermined gap therebetween, and the amount of light permeating the substrates is controlled by the electric field applied to the liquid crystal. A plurality of pixel electrodes and TFTs are formed on the TFT substrate, and a RGB color filter and a black matrix are formed on the CF substrate.
To improve productivity in the TFT-LCD manufacturing process, a mother glass substrate forms a plurality of panels (hereinafter, xe2x80x9ccellxe2x80x9d) on it, and each cell forms one TFT-LCD panel. In other words, after forming a plurality of cells (e.g., 4, 6, 8 cells) on a whole TFT substrate and a whole CF substrate, the two substrates are assembled together and cut into each of the TFT-LCD panel. However, while manufacturing the whole TFT and CF substrates, defects may occur in one or more of the cells. If one of the substrate of a TFT-LCD panel is defective, the entire resulting TFT-LCD panel must be discarded.
To solve the above problem, the whole TFT and CF substrates having defective cells are cut, for example, to one-half or one-third size, sorted by defects, and assembled together for TFT-LCD panels.
FIG. 1 shows a block diagram of a cutting and sorting system used in the conventional TFT-LCD manufacturing process. As shown in the drawing, cutting and sorting are realized through two separate lines of equipment. A substrates is cut in a substrate cutting line 10 and the cut substrates are sorted in a substrate sorting line 20.
The substrate cutting line 10 comprises a cutting loader 11, a cutter 12, and a cutting unloader 13; while the substrate sorting line 20 comprises a sorting loader 21, a sorter 22, and a sorting unloader 23. A substrate (either a whole TFT substrate or a whole CF substrate) having defective cells is supplied to the cutting loader 11 of the substrate cutting line 10. The substrate is then transferred to the cutter 12 where the substrate is cut to xc2xd or ⅓ size. When the substrate has a total of six cells formed thereon, the substrate is cut into two or three sections, each section having either three or two cells, respectively.
The cut substrate is then transferred to the cutting unloader 13 of the substrate cutting line 10, and the cutting unloader 13 supplies the cut substrate to a conveyor 30 provided between the substrate cutting line 10 and the substrate sorting line 20. After a predetermined number of cut substrates has been supplied to the conveyor 30 in this manner, the conveyor 30 then supplies the substrates to the sorting loader 21 of the substrate sorting line 20. Next, the sorting loader 21 transfers the cut substrates to the sorter 22. The sorter 22 sorts out the substrates according to predetermined grades and sends them to the sorting uloader 23. The sorting unloader 23 stores them in a plurality of cassettes 24a, 24b, 24c according to a grade.
In a conventional TFT-LCD manufacturing process, substrates having defective cells are cut and sorted in two separate process lines as described above, and a conveyor for the substrates is provided between the two lines. As a result, overall manufacturing costs are increased by the large amount of equipment used. Further, such a separation of processes increases the time for manufacturing TFT-LCDs and thereby lowers the overall productivity.
The present invention has been made in an effort to solve the above problems.
It is an object of the present invention to provide a cutting and sorting automation system and a method for controlling the same that simultaneously cuts and sorts defective substrates to reduce manufacturing costs and enhance productivity in a TFT-LCD manufacturing process.
To achieve the above object, the present invention provides a cutting and sorting automation system and a method for controlling the same. The system includes a cutting/sorting equipment for cutting a substrate having a plurality of cells to form cut substrates, and sorting the cut substrates according to a predetermined mode; and a system controller for receiving a request for operation information on the cut substrates from the cutting/sorting equipment, and transmitting the operation information and operation commands to the cutting/sorting equipment.
According to a feature of the present invention, the cutting/sorting equipment includes a loader for receiving a cassette storing the substrate from a stocker or such an equipment, and holding the cassette; a cutter for receiving the substrate in the cassette from the loader and cutting the substrate to predetermined sizes to form the cut substrates; a substrate ID reader for reading IDs of the cut substrates received from the cutter; and an unloader for receiving the cut substrates from the substrate ID reader, and sorting the cut substrates according to a read result of the cut substrates and a predetermined operating mode.
According to another feature of the present invention, the substrate ID reader includes a handling table on which the cut substrates are placed; and a cut substrate reader for reading the IDs of the cut substrates to determine a position and a defective grade of the cut substrates.
According to yet another feature of the present invention, the unloader includes a cassette storing station on which a plurality of cassettes containing the cut substrates are placed; and a first conveying robot supplying each of the cut substrates in one of the cassettes on the cassette storing station according to what the cut substrate reader has read and a predetermined operating mode.
According to still yet another feature of the present invention, the loader includes a plurality of ports on which the cassette storing the substrate is placed; and a second conveying robot for removing the substrate from the cassette placed on one of the ports and sending the substrate to the cutter.
According to still yet another feature of the present invention, the operating mode is a sequence mode in which the cut substrates are supplied to the cassettes placed on the cassette storing station in sequence, i.e., to one of the cassettes until the cassette is full, then to the subsequent cassette.
According to still yet another feature of the present invention, the operating mode is a position mode in which the cut substrates are supplied to the cassettes placed on the cassette storing station according to a position from which the cut substrates were cut from the uncut substrate.
According to still yet another feature of the present invention, the operating mode is a grade mode in which the cut substrates are supplied to the cassettes placed on the cassette storing station according to predetermined defective grades of the cut substrates.
The method includes the steps of (a) determining an operating mode; (b) sorting the cut substrates and supplying the sorted cut substrates to one of the plurality of cassettes according to the operating mode; and (c) repeating steps (a) and (b) for a predetermined lot number of cut substrates.
According to a feature of the method of the present invention, the step (b) further includes the steps of receiving cut substrate information including a cut substrate ID and a cut substrate grade from a host; determining grades of the cut substrates based on the information transmitted from the host by reading the IDs of the cut substrates; and supplying the cut substrates to the cassettes according to the grades of the cut substrates.